Satellite Imagery and Remote Sensing

Watch

• Eyes in the Sky Satellite Imagery to Track Global Environmental Change ↗IUCN Global Youth Summit
• From Pixels to Products: An Overview of Satellite Remote Sensing ↗NASA Earthdata
• How Satellites Know What Is Happening on Earth ↗Whatly
• I Couldn't Find a Video Explaining Satellite Images, So I Made One ↗Max Lenormand
• OSINT At Home #9 – Top 4 Free Satellite Imagery Sources ↗Bendobrown
• Cindy Schmidt: Finding A Career in Remote Sensing and Geographic Information Systems ↗NASA Video

Read

• An Introduction to Remote Sensing ↗An accessible entry point, this volume demystifies the complex world of satellite imagery, making its fundamental concepts digestible for the uninitiated.James B. Campbell and Randolph H. Wynne
• Remote Sensing and Image Interpretation ↗This authoritative text provides a comprehensive grounding in the principles and applications of remote sensing, essential for any serious student of Earth observation.Thomas M. Lillesand, Ralph W. Kiefer, and Jonathan W. Chipman
• Remote Sensing of the Environment: An Earth Resource Perspective ↗A foundational work, this book meticulously details the physical principles and diverse applications of remote sensing, offering a vital resource for environmental analysis.John R. Jensen
• Remote Sensing: The First 50 YearsThis retrospective offers a concise yet comprehensive overview of remote sensing's evolution, charting its transformative impact on environmental science over five decades.Michael E. Schaepman, Michael F. Goodchild, and Susan L. Ustin
• Global Forest Watch: The First 5 YearsThis paper showcases the unprecedented utility of satellite data in monitoring global forest change, demonstrating its critical role in environmental governance and conservation.Matthew C. Hansen, Peter V. Potapov, Alexandra Tyukavina, David M. Laporte, Alexander V. Goetz, Stephen V. Stehman, and Thomas R. Loveland

Voices to follow

• Sarah Parcak ↗A pioneer in 'space archaeology', she leverages satellite imagery to uncover lost ancient civilisations, demonstrating the technology's profound historical utility.Professor of Archaeology, University of Alabama at Birmingham; National Geographic Explorer
• Karen Seto ↗Her extensive work on urbanisation and land-use change, meticulously documented through satellite data, offers critical insights into global environmental transformations.Frederick C. Hixon Professor of Geography and Urbanization Science, Yale University
• Andrew Tatem ↗He leads efforts to map human populations with unprecedented detail using satellite imagery, providing essential data for public health, disaster response, and development planning.Professor of Geography and Environmental Science, University of Southampton; Director of WorldPop
• Dawn Wright ↗As a leading voice in geographic information science, she champions the integration of satellite data with GIS to advance understanding of marine environments and broader geospatial challenges.Chief Scientist, Esri; Professor of Geography and Oceanography, Oregon State University

Glossary

• ApplicationAn application refers to the practical ways satellite imagery and remote sensing are used to solve real-world problems or help us understand our planet. It's about putting the technology to work. For example, one application is using satellite images to track deforestation in the Amazon rainforest, helping conservationists protect the environment.
• DataIn remote sensing, data refers to the raw information collected by satellite sensors, such as measurements of light, heat, or other energy. This raw information is then processed to create images or other useful products. For example, when a satellite measures the brightness of different colors reflected from a field, those measurements are the data that can later be turned into an image showing crop health.
• Electromagnetic SpectrumThe electromagnetic spectrum is the entire range of all types of light, from radio waves to X-rays, including the visible light we can see. Remote sensing satellites use sensors that can detect different parts of this spectrum to gather various kinds of information. For example, while our eyes only see visible light, a satellite sensor might detect infrared light to show how healthy plants are, even if they look green to us.
• Geographic Information System (GIS)A GIS is a computer system that lets you store, analyze, and display all types of geographic data, like maps and satellite images. It helps us understand patterns and relationships on Earth. For example, city planners might use GIS to combine satellite images with data about population and traffic to decide where to build new roads or schools.
• GPS (Global Positioning System)GPS is a satellite-based navigation system that provides location and time information anywhere on Earth where there is an unobstructed line of sight to four or more GPS satellites. It tells you exactly where you are. For example, when you use your phone's map app to find directions to a friend's house, you're using GPS.
• PixelA pixel is the smallest individual square dot or "picture element" that makes up a digital image, including satellite images. When you zoom in really close on an image, you start to see these tiny squares. For example, if you look very closely at a photo on your phone, you'll eventually see the tiny colored squares (pixels) that create the whole picture.
• Remote SensingRemote sensing is a way of gathering information about Earth's surface or atmosphere without actually touching it. It uses special tools, often on satellites or airplanes, to collect data from a distance. For example, when a satellite takes pictures of a forest from space to see if it's healthy, that's remote sensing.
• Resolution (Spatial Resolution)Resolution, specifically spatial resolution, describes how much detail a satellite image can show. A higher resolution means the image can distinguish smaller objects on the ground, making the picture clearer. For example, an image with high resolution might clearly show individual cars on a road, while a low-resolution image might only show the road itself.
• Satellite ImagerySatellite imagery refers to pictures of Earth taken from space by artificial satellites orbiting our planet. These images show us what different parts of the world look like from above. For example, the maps you see on Google Earth use satellite imagery to show you buildings, roads, and natural landscapes.
• SensorA sensor is a device on a satellite or aircraft that collects information by detecting energy reflected or emitted from Earth's surface. Think of it like a super advanced camera that can "see" more than just visible light. For example, a sensor on a weather satellite might detect heat to show us where storms are forming, even at night.

Threads 5

Where this connects to other fields, and why it's worth knowing.

• Signal & Image Processing Mathematics

  A satellite 'photo' of Earth isn't really a photo. It's a picture rebuilt from raw sensor readings using the same math that turns an MRI scan into an image of your knee. In both cases you never see the thing directly; you work backward from clues to reconstruct what must be there, which mathematicians call solving an inverse problem.

• International & Human Rights Law Law

  Satellites can now photograph mass graves and prison camps from space. That flipped human-rights cases from relying on shaky eyewitness stories, which are easy to deny, to hard pixels you can point at. An atrocity used to be someone's word; now it can be an image from orbit that the whole world can check.

• Astronomy & Cosmology Science

  The same kind of instruments astronomers point at distant stars get flipped around to stare back at Earth, watching forests, ice, and storms. It's astronomy turned inward. And when astronauts actually saw the whole fragile planet floating in black space, that gut-punch feeling, the 'overview effect', helped kick-start the environmental movement.

• Scientific Instruments & Measurement Science

  You can only know what you can detect. Every new kind of satellite sensor, one that sees heat, or sees through clouds, or splits light into hundreds of colors, suddenly reveals things that were hidden: secret deforestation, illegal brick kilns, all exposed overnight. New instruments don't just measure the world, they change what can be caught.

• Carbon Markets & Net Zero Environment

  Companies buy 'permits' to pollute and swear they've cut their emissions, but how do you catch one lying? Satellites can now photograph invisible methane leaking from a single site from space. So making a pollution market actually work turns out to depend on being able to measure cheating from orbit.